Heat exchangers

ABSTRACT

A heat exchange element having a hollow body through which a first fluid may flow for heat exchange with a second fluid outside the element. The element is made of two sheets, at least one of which is corrugated with the plates being welded along their points of contact to form a series of internal flow passages.

United States Patent [191' Merryfull [451 Sept. 11, 1973 HEAT EXCHANGERS [76] Inventor: Albert Edward Merrytull, 17 Ayres Rd. East, St. Ives, New South Wales,

Australia [22] Filed: Mar. 23, 1971 [21] Appi. No; 127,229

[52] US. Cl. 165/1'70 [51'] Int. CI..L F28b 3/00 [58] Field of Search; 165/166, 170, 157,

[56] References Cited UNITED STATES PATENTS 2,129,473 9/1938 MoJonnier et al 165/17 UX 3,216,494 11/1965 Goodman 165/166 3,111,982 11/1963 Ulbricht [65/166 2,060,211 11/1936 Hemphi11.. 165/170 1,863,555 6/1932 Castiaux 165/170 X Primary Examiner--Charles J. Myhre Assistant Examiner-Theophi1 W. Streule, Jr. Attorney-Stevens, Davis, Miller & Mosher [57] ABSTRACT A heat exchange element having a hollow body through which a first fluid may flow for heat exchange with a second fluid outside the element. The element is made of two sheets, at least one of which is corrugated with the plates being welded along their points of contact to form a series of internal flow passages.

2 Claims, 10 Drawing Figures PATENTEUSEPI 1 I973 SHEET 2 BF 3 FIG.

PATENTEUSE" 3.757.857

' SHEET 3 0F 3 HEAT EXCHANGERS This invention relates to heat exchange elements of the kind comprising a hollow body through the interior of which a first fluid may flow for heat exchange with a second fluid flowing over the outside of the body.

Usually, the body is made of metal because of the high thermal conductivity of metals, but heat exchange elements of the kind under discussion may at times be made of other materials, for example, plastics materials.

Usually, the body is shaped so as to provide a large area of interface between the two fluids. Furthermore,

fins or other extended surfaces may be provided to increase the effective area. Thus, acommonplace type of heat exchanger comprises a tortuous metallic tube brazed to a metal sheet. Another similar conventional heat exchanger comprises a metal sheet, header tubes at opposite edges thereof and a plurality of further tubes brazed to the sheet and extending from one header tube to the other.

An object of the present invention is to provide a heat exchange element of platelike shape which is simpler to construct and more efficient than the above described conventional elements.

The invention consists in a heat exchange element comprising two plates superimposed one upon the other and sealed about their peripheries in a fluid-tight manner; at least one of said plates being continuously corrugated and the plates being welded or otherwise secured together at selected positions so as to define one or more fluid passageways between the plates.

By way of example, several embodiments of the above described invention are described hereinafter with reference to the accompanying drawings.

FIG. l-is a side elevation of a'heat exchange element in accordance withthe invention.

FIG. 2 is a view of the heat exchange element of FIG. 1 taken on line 2-2 of that Figure.

FIG. 3 is a sectional view taken on line 3-3 of FIG. 1 drawn to a larger scale.

FIG. 4 is a view similar to FIG. 1 of a portion of a second form of heat exchange element in accordance with the invention. I

FIG. 5 is a view on line 5-5 of FIG. 4.

FIG. 6 is a view similar to FIG. 1 of a portion of a third form of heat exchange element in accordance with the invention. l

FIG. 7 is a view taken'on line 77 of FIG. 6.

FIG. 8 is a view similar to FIG.1 of a fourth form of heat exchange element according to the invention.

FIG. 9 is a view taken on line 9--9 of FIG. 8 drawn to a larger scale.

FIG. 10 is a view taken on line 10-10 ofFIGS. 8 and 9 drawn to a larger scaletha'n FIG. 8.

The heat exchange element illustrated by FIGS. 1 to 3 comprises two header tubes 11 with two corrugated plates 12 superimposed one upon the other and extendingfrom one header tube to the other. The plates 12 are arranged (as may best be seen in FIG. 3) with the troughs of the corrugations in one plate contacting the crests of the corrugations in the other so that the plates 12 define between them a plurality of parallel fluid passages 13.

The side edges of the plates 12 at each of the tubes 11 are continuously welded to the tubes and the tubes 11 have orifices in them communicating respectivey with the fluid passages 13.

gether by spaced apart weld spots on those lines of con tact.

The top and bottom edges of the plates 12 may be extended as flanges 14 with the flanges at each edge welded together continuously along their tips.

To promote turbulence in the fluid flowing along the passages 13 the corrugations in the plates 12 are stepped along step lines 15 so that portions of the passageways on each side of the step lines are offset slightly one from the other.

In use, a first fluid is introduced into one header tube 11 and flows through the passageways 13 to the other header tube 11 and a second fluid is allowed to flow as a' thin film down the outer surfaces of the plates 12.

The embodiment of the invention illustrated by FIGS. 4 and 5 comprises two plates 12A corrugated and welded together in the manner of plates 12 of the FIG. 1 embodiment of the invention but instead of terminating at opposite edges in header tubes 11 the plates 12A are formed with channelshapededge margins "16- extending transversely of the corrugations in the plate and defining header passages 17. l The FIGS. 4 and 5 embodiment of the invention functions in exactly the same way as the FIGS. 1 to 3 embodiment with the header passages 17 taking the place of the interior of the tubes 11. i

The heat exchange element illustrated by FIGS. 6 and 7 is similar in construction to that of FIGS. 4 and viding communication between the interior of neighbouring fluid passageways corresponding to passageways 13 are provided in place of channels 16. The lengths of channel 16A at each side edge of the element are staggered so that a tortuous flow path for the fluid between the two plates is defined insteadof the plurality of parallel flow paths of the two first described embodirnents of the invention.

The heat exchange element illustrated by FIGS. 8 and 10 is one primarily intended as a vertical flow exchanger; that is, one in which the liquid to be cooled descendsexternally by gravity and the cooling medium inside the exchanger rises therein. This exchangeelement is essentially similar to that of FIG. 1' except that the contact between the two plates except at their edges is restricted to contact between wells 18 formed in the troughs of the corrugations inone of the plates and correspondingly positioned mounds 19 formed on the crests of the corrugations in the other plate.

The wells 18 and mounds 19 are disposed intermediate the step lines in the corrugations of the plates and are shorter thanthe corrugation length between one step and the next. Thus, cross-passages 20 are formed putting the interiors of neighbouring fluid passageways corresponding to fluid passageways 13 into communication one with the other.

In the embodiment of the invention now being described, therefore, fluid between the plates may flow along a multiplicity of paths defined in part by short lengths of said fluid passageways in part by said crosspassages. It will be appreciated that heat exchange elements in accordance with the invention may differ from the examples illustrated in the accompanying drawings. For example, one of the plates may be non-corrugated, in which event, the fluid passageways are defined besion, said plates being positioned so that contact between the plates, except at their edges, is restricted to elongated contact areas between said wells and said mounds with cross passages between neighbouring fluid passageways being defined between the contact areas.

2. A heat exchange element according to claim 1 wherein the corrugations on at least one plate are stepped along step lines extending transversely of the corrugations. 

1. A heat exchange element comprising two continuously corrugated plates superimposed one upon the other and sealed about their peripheries in a fluid-tight manner to define fluid passageways between the plates; spaced apart wells formed in the troughs of the corrugations of one plate; correspondingly positioned mounds formed on the crests of the corrugations of the other plate, said wells and mounds boTh having a longitudinal dimension greater than their transverse dimension, said plates being positioned so that contact between the plates, except at their edges, is restricted to elongated contact areas between said wells and said mounds with cross passages between neighbouring fluid passageways being defined between the contact areas.
 2. A heat exchange element according to claim 1 wherein the corrugations on at least one plate are stepped along step lines extending transversely of the corrugations. 